|Ship Name|In Service|Project Number|Type|Class|Comments|
|---|---|---|---|---|---|
|Lenin|1959|92M|Icebreaker|—|Decommissioned 1989. Museum ship.|
|Arktika|1975|1052-1|Icebreaker|Arktika|Not operational.|
|Sibir|1977|1052-2|Icebreaker|Arktika|Defueled and not operational since 1993.|
|Rossiya|1985|10521-1|Icebreaker|Arktika||
|Sevmorput|1988|10081|Container ship|—|Has ice-breaking bow|
|Taymyr|1989|10580-1|River icebreaker|Taymyr||
|Sovetskiy Soyuz|1990|10521-2|Icebreaker|Arktika||
|Vaygach|1990|10580-2|River icebreaker|Taymyr||
|Yamal|1993|10521-3|Icebreaker|Arktika||
|50 Let Pobedy|2007|10521|Icebreaker|Arktika|Built as Ural, completed in 2007.|

Question: how many years later was the sibir in service after the lenin?
Answer: 18